Step 1: Calculate Your Basal Metabolic Rate (BMR)
The clinical gold standard for population estimates is the Mifflin-St Jeor Equation:
For Men:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
For Women:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
Step 2: Apply Your Physical Activity Multiplier (PAL)
Multiply your BMR from Step 1 by your physical activity level. To eliminate guesswork, use your empirical average daily step count:
Sedentary: BMR × 1.2
< 5,000 steps/day. Desk job, little to no structured workouts.
Lightly Active: BMR × 1.375
5,000–7,500 steps/day. Light exercise 1–3 days/week.
Moderately Active: BMR × 1.55
7,500–10,000 steps/day. Moderate exercise 3–5 days/week.
Very Active: BMR × 1.725
10,000–13,000 steps/day. Hard exercise 6–7 days/week.
Step 3: An Example Calculation
Profile: 30-year-old male, 80 kg (176 lbs), 180 cm tall, moderately active (8,000 steps/day).
- BMR = (10 × 80) + (6.25 × 180) - (5 × 30) + 5 = 800 + 1,125 - 150 + 5 = 1,780 kcal
- TDEE = 1,780 × 1.55 = 2,759 kcal/day
Eating 2,759 calories a day will maintain this individual's bodyweight. To lose 1 lb of fat per week, he would eat ~2,259 kcal/day (a 500 kcal deficit).